Examine the difference between a charger chip and a microcontroller.
When first introduced in the 1980s, charger chips simplified the design of NiCd and MiMH chargers, as batteries with these chemistries were difficult to charge. Li-ion is simpler and most modern charging chips also include the protection circuits that are needed to safe charge Li-ion. These are current and voltage regulation, FET switches and may also include charge status indicators and cell balancing. Added to most chips is a time-out-timer that halts charge if predictable symptoms do not occur in time when charging a flawed battery.
Advanced chips also feature pre-charge conditioning (boost) for inactive batteries and a sleep mode that reduces the power when the job is done. On batteries that draw a load while on charge, some chips automatically restart charge when the voltage falls below a preset voltage threshold.
Although charger chips are easy and economical to use, they have limitations. Most offer a fixed charge algorithm that does not permit fine-tuning for specialty uses. Chips are made for a given battery and may not accommodate different chemistries selectable by the user or read by a battery-embedded code. Nor do most chips adjust to an optimal charge current when charging an aging battery with reduced charge acceptance.
Microcontrollers offer an alternative to charger chips. Although the design cost is higher because of the extra programming time needed, manufacturing costs are compatible to charger chips. It should be noted that the charge chip or the microcontroller only form a small part of the charger circuit; the bulk of the cost lies in the peripheral components, which include solid-state switches, signal lights and the power supply. The cost of these parts is directly related to current handling.
Charger modules are also available that can be programmed to a charge algorithm, voltage and current. Some have seamless DC-DC conversion so that a low input voltage can charge a battery of higher voltage. Some charger modules offer options for solar charging, SMBus, discharge for calibration and a display. Using soft-programmable charger modules resembles the ready-made AC power supplies that became popular in the 1990s as a lower cost alternative to building one’s own charger.
Last updated 2015-11-11
Comments are intended for "commenting," an open discussion amongst site visitors. Battery University monitors the comments and understands the importance of expressing perspectives and opinions in a shared forum. However, all communication must be done with the use of appropriate language and the avoidance of spam and discrimination.
If you have a question, require further information, have a suggestion or would like to report an error, use the "contact us" form or email us at: BatteryU@cadex.com. While we make all efforts to answer your questions accurately, we cannot guarantee results. Neither can we take responsibility for any damages or injuries that may result as a consequence of the information provided. Please accept our advice as a free public support rather than an engineering or professional service.